Effect of error field correction coils on W7-X limiter loads

Bozhenkov, Sergey A.; Jakubowski, M. W.; Niemann, H.; Lazerson, S. A.; Wurden, G. A.; Biedermann, C.; Kocsis, G.; König, R.; Pisano, F.; Stephey, L.; Szepesi, T.; Wenzel, U.; Pedersen, T. S.; Wolf, R. C.

doi:10.1088/1741-4326/aa85ce

Effect of error field correction coils on W7-X limiter loads

Journal Article · Wed Sep 27 00:00:00 EDT 2017 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/aa85ce· OSTI ID:1466524

Bozhenkov, Sergey A. ^[1]; Jakubowski, M. W. ^[1]; Niemann, H. ^[1]; ^[2]; ^[3]; Biedermann, C. ^[1]; Kocsis, G. ^[4]; König, R. ^[1]; Pisano, F. ^[5]; Stephey, L. ^[6]; Szepesi, T. ^[4]; Wenzel, U. ^[1]; Pedersen, T. S. ^[1]; Wolf, R. C. ^[1]

Max-Planck-Institut fur Plasmaphysik, Greifswald (Germany)
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Wigner Institute, Budapest (Hungary)
Univ. of Cagliari (Italy)
Univ. of Wisconsin, Madison, WI (United States)

In the first campaign Wendelstein 7-X was operated with five poloidal graphite limiters installed stellarator symmetrically. In an ideal situation the power losses would be equally distributed between the limiters. The limiter shape was designed to smoothly distribute the heat flux over two strike lines. Vertically the strike lines are not uniform because of different connection lengths. In this paper it is demonstrated both numerically and experimentally that the heat flux distribution can be significantly changed by non-resonant $n=1$ perturbation field of the order of $$10^{-4}$$ . Numerical studies are performed with field line tracing. In experiments perturbation fields are excited with five error field trim coils. The limiters are diagnosed with infrared cameras, neutral gas pressure gauges, thermocouples and spectroscopic diagnostics. Experimental results are qualitatively consistent with the simulations. With a suitable choice of the phase and amplitude of the perturbation a more symmetric plasma-limiter interaction can be potentially achieved. Finally, these results are also of interest for the later W7-X divertor operation.

Research Organization:: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: EUROfusion Consortiumand has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053.; USDOE

Contributing Organization:: W7-X Team

OSTI ID:: 1466524

Alternate ID(s):: OSTI ID: 22925954

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 12 Vol. 57; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (15)

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Magnetic configuration effects on the Wendelstein 7-X stellarator Dinklage, A.; Beidler, C. D.; Helander, P. Nature Physics, Vol. 14, Issue 8 https://doi.org/10.1038/s41567-018-0141-9	journal	May 2018
Wall conditioning by ECRH discharges and He-GDC in the limiter phase of Wendelstein 7-X Wauters, T.; Brakel, R.; Brezinsek, S. Nuclear Fusion, Vol. 58, Issue 6 https://doi.org/10.1088/1741-4326/aab2c9	journal	April 2018
Measurements and correction of the 1/1 error field in Wendelstein 7-X Bozhenkov, S. A.; Otte, M.; Biedermann, C. Nuclear Fusion, Vol. 59, Issue 2 https://doi.org/10.1088/1741-4326/aaf20c	journal	December 2018
Methods for quantitative study of divertor heat loads on W7-X Gao, Y.; Jakubowski, Marcin W.; Drewelow, Peter Nuclear Fusion, Vol. 59, Issue 6 https://doi.org/10.1088/1741-4326/ab0f49	journal	April 2019
Features of near and far scrape-off layer heat fluxes on the Wendelstein 7-X inboard limiters Niemann, H.; Jakubowski, M. W.; Effenberg, F. Nuclear Fusion, Vol. 60, Issue 1 https://doi.org/10.1088/1741-4326/ab472c	journal	November 2019
Magnetic configuration effects on the edge heat flux in the limiter plasma on W7-X measured using the infrared camera and the combined probe Drews, P.; Niemann, H.; Cosfeld, J. Plasma Science and Technology, Vol. 20, Issue 5 https://doi.org/10.1088/2058-6272/aaa968	journal	April 2018

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70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Wendelstein 7-X
error fields
limiter
limiter symmetry
stellarator fields

Effect of error field correction coils on W7-X limiter loads

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